Sarah Soliz,Director of Quality Programs,is Designing and R Charts for the Rod

Multiple Choice

Sarah Soliz,Director of Quality Programs,is designing and R charts for the rod shearing process at Stockton Steel.She has 26 samples of rod length,and each sample included measurements of 5 rods.The mean of the 26 sample means is 112 centimetres,and mean of the 26 ranges is 0.15 centimetres.The centerline for her R chart is ___.

A) 0.15
B) 26
C) 5
D) 112
E) 15